a preliminary selection list, as they had done in the T4 operation. This left just a few questions to be answered, such as personal information, date of admission to the camp, diagnosis of incurable disease, war injuries, criminal referral based on the German penal code and any previous offenses. Names of ballastexistenzen (dead weight prisoners) were to be compiled and presented to the medical doctors for withdrawal from service, which included any prisoner who had been unable to work for a long time or was substantially incapacitated and would not be able to return to work. Prisoners in the preliminary selection had to report to the medical panel but there was no proper medical examination; the prisoners were questioned about their participation in World War I and about any war medals they might have received. Based on personnel and medical records, the panel decided how to classify each of the prisoners. The final assessment was made using the information in the reporting form and was limited to the decision as to whether or not the prisoner would be steered toward "special treatment" 14f13. The report form and results were sent for documentary registration at the T4 central office in Berlin. Prisoners being considered for the preliminary selection were sometimes encouraged by the camp administration to come forward if they felt sick or unable to work. They were led to believe they would go to a "recovery camp", where they would have light duties. Many prisoners believed the lie and readily volunteered but, after they were gassed at the killing centers, the victims' belongings were sent back to the camp warehouse for sorting. Prisoners learned the true reason for the selection and even prisoners with serious illnesses stopped reporting to the infirmary. The first known selection took place in April 1941 at Sachsenhausen concentration camp. By the summer, at least 400 prisoners from Sachsenhausen had been murdered. During the same period, 450 prisoners from Buchenwald and 575 prisoners from Auschwitz were gassed at the Sonnenstein Killing Facility; Hartheim Killing Facility was used to murder 1,000 prisoners from Mauthausen concentration camp. Between September and November 1941, 3,000 prisoners from Dachau and several thousand people from Mauthausen and neighboring Gusen concentration camp, were gassed at Hartheim. Prisoners from the Flossenbürg, Neuengamme and Ravensbrück camps were also selected and murdered. After November, another 1,000 prisoners from Buchenwald, 850 from Ravensbrück and 214 from Groß-Rosen,